Chapter Questions
The integrative functions of the nervous system are performed mainly bya. afferent neurons.b. efferent neurons.c. neuroglia.d. sensory neurons.e. interneurons.
The highest density of voltage-gated ion channels is found in the _____ of a neuron.a. dendritesb. neurosomac. myelin sheath gapsd. internodal segmentse. axon terminals
The neurosoma of a mature neuron lacksa. a nucleus.b. endoplasmic reticulum.c. lipofuscin.d. centrioles.e. ribosomes.
The glial cells that fight infections in the CNS area. microglia.b. satellite cells.c. ependymal cells.d. oligodendrocytes.e. astrocytes.
Posttetanic pocentiation of a synapse incresses the amount of _____ in the axon terminal.a. neurotransmitterb. neurotransmitter receptorsc. calciumd. sodiume. NMDA
An IPSP is _____ of the postsynaptic ne.uron.a. a refractory periodb. an action potentialc. a depolarizationd. a repolarizatione. a hyperpolarization
Saltatory conduction occurs onlya. at chemical synapses.b. in the initial segment of an axon.c. in both the initial segment and axon hillock.d. in myelinated nerve fibers.e. in unmyelinated nerve fibers.
Some neurotransmitters can have either excitatory of inhibitory effects depending on the type ofa. receptors on the postsynaptic cell.b. synaptic vesicles in the axon.c. synaptic potentiation that occurs.d. postsynaptic potentials on the axon terminal.e. neuromodulator involved.
Differences in the volume of a sound are likely to be encoded by differences in _____ in nerve fibers from the inner ear.a. neurotransmittersb. signal conduction velocityc. types of postsynaptic potentialsd. firing frequencye. voltage of the action potentials
Motor effects that depend on repetitive output from a neural pool are most likely to usea. parallel after-discharge circuits.b. reverberating circuits.c. Facilitated circuits.d. diverging circuits.e. converging circuits.
Neurons that convey information to the CNS are called sensory, or _____ neurons.
To perform their role, neurons must have the properties of excitability, secretion, and _____.
The _____ is a period of time in which a neuron is producing an action potential and cannot respond to another stimulus of any strength.
Neurons receive incoming signals by way of specialized extensions of the cell called ______.
In the CNS, myelin is produced by glial cells called _____.
A myelinated nerve fiber can produce action potentials only in specialized regions called _____.
The trigger zone of a neuron consists of its _____ and _____.
The neurotransmitter secreted at an sdrenergice synapoe is _____
A presynaptic nerve fiber cannot cause other neurons in its _____ to fire, but it can make them more sensitive to stimulation from other presynaptic fibers.
_____ are substances released along with a neurotransmitter that modify the neurotransmîtter's effect.